Am I the only one who's ROA isn't reliable?

[rking22]

Just a thought, but does the hammer show any sign of dragging on the frame? Could be some interference that is slowing the hammer strike. Perhaps the mainspring strut even?? Try cocking, then slowly lower the hammer paying particular attention to any change in the feel, a bump or lessening of the force required to hold it from falling free. Do it very slowly.
A question, if you mark the chambers, 1 thru 6, does the misfire repeat on a particular group of chambers? This has become and interesting issue, but then it ain’t my gun

[megasupermagnum]

No, the hammer seems free and smooth as any revolver I have. I have tried marking the chambers. There is no correlation, the problem is entirely random. The ones that do not go off have a perfect hammer shaped dent right in the perfect center of them. It is not hitting to the side, or too high or low. It is not hitting off square. It is hitting the caps perfectly centered and squared on every cylinder.

I've never owned another CB revolver, but I can put these caps on any other gun of mine, and they will go off every time. Last year I fired something like 600 of these caps, and not a single failure.

It is baffling. The only thing I can think of is that most guns have a hammer that is larger than the cap. They hit the entire surface. On this ROA, the hammer face is rectangular, maybe half the width of a cap. On the caps that do not fire, if I pull them off and look at them, I see that the priming compound is buckled.

[rking22]

I believe my hammer nose covers the whole cap, but relying on memory. Can you measure width of yours? I will try to get my gun out and check when I get home. That could be the issue, the hammer is common component to all the nipples you have tried.

[rking22]

My hammer nose is .155 wide wher it contacts the cap and shows a witness mark from where the caps are.

[megasupermagnum]

Holy Smokes, big development!

Since it is still covered in soot from previous failures, I was able to see something I never would have clean. If you look close at the first picture, the left side of the hammer face is rounded off. The second picture is more telling, the hammer face is clearly impacting the frame. You can't feel this at all when manipulating the hammer normally by hand, but you can see it hits when fired.

This has to be it, nothing else makes sense. I have some left over trigger shims from my other Ruger's. I'll try and shim the hammer to the right, and try it in the morning. The hammer face is about .150" wide.

[arcticap]

"Based on a test using a 2 kilogram weight (4.40924524 lbs.), the impact sensitivity of lead styphnate is 3 inches."

If enough force contacts the cap and it's well seated, it will go off.
FWIW my mention about beefing up the main spring is called piggy backing.
Perhaps depending on where the additional load is placed on the main spring, it will affect the resulting characteristic differently compared to shimming with washers.

The caps have a length as well as a diameter.
A cap can fit loose in diameter, but still be too tall so that the nipple taper prevents it from being seated all of the way down on the cap.
That's why some folks use a push stick to seat the caps.
And also why some cap brands work better than others.
Even magnum caps have more primer material inside the cap which can affect how well it seats on the nipple and whether the impact is cushioned or not.
Maybe if a cap fits loose, it can come up and off being seated on the nipple as each shot is fired.
Whereas a snug fitting #10 cap won't do that and will stay in place.
But then staying in place may result in too much clearance.

And that may also correlate to why the Slix Shot or Ampco nipples may work better.
If the cone is taller then that may effectively raise the caps increasing the hammer impact, and the caps may also seat better if the cones are taller by even a small amount.

There's still a chance that the cylinder is not remaining static when the hammer falls, or that there is slight interference with the hammer in the slot or both, in addition to the clearance related issues.

To be honest, .003 clearance seems a little bit excessive if it's an accurate measurement.
You may need to try different nipples, in addition to either shimming both the nipples and mainspring.
And maybe even try to slick up the hammer fall with a lubricant such as graphite or a compatible oil.

There may even be a way to modify how far the hammer can fall forward as someone else previously mentioned if the frame or hammer design interferes with or limits how far that it can fall.
That could be fairly simple.
It's a project to not give up on if you bought the gun at a good deal.
If Ruger will look at it then that's always a possibility.
But I know someone who had a defective ROA and Ruger offered him any current model as a replacement rather than fixing it since they didn't have the replacement parts needed.

I hope that #10 caps or #10 Remingtons are the simple solution.

[megasupermagnum]

Upon closer inspection, the hammer is way off. There is quite a bit of slop on the hammer to frame groove, but I'm not certain shims alone will fix this.

This is going to sound bizarre, but I took the gun apart so I could watch everything in motion. With the hammer pushed all the way to the right against the frame, the hammer nose hits the left side as it enters the slot, as bad or worse than with everything assembled. Then with the hammer pushed all the way to the left, the hammer nose seems to enter the slot perfectly straight, and only with the slightest resistance.

So we have two strange things going on. One, there is more slop around the hammer than I'm used to on Ruger. This one accepts a .015" feeler gauge. The other is that something on the right side is out of square, either the hammer or unfortunately likely the frame itself. If the hammer was off or bent, then pushing it to the left side of the frame should make the problem worse. In fact pushing to the left allows the hammer straight.

I've tried a few comb's of shims with no real success. Even with all shims on the right side, it seems to force the hammer off square. I think what I'll do is call Ruger and see if they will look at it. If all else fails, I'm thinking one option might be to mill off the hammer on the left side. Not the body, just the nose of the hammer that fits in the slot. Unfortunately it appears that I would likely have to take off as much as .025" or so.

At least I know what the problem is now. Now I just need to fix it.

[megasupermagnum]

"Based on a test using a 2 kilogram weight (4.40924524 lbs.), the impact sensitivity of lead styphnate is 3 inches."

If enough force contacts the cap and it's well seated, it will go off.
FWIW my mention about beefing up the main spring is called piggy backing.
Perhaps depending on where the additional load is placed on the main spring, it will affect the resulting characteristic differently compared to shimming with washers.

The caps have a length as well as a diameter.
A cap can fit loose in diameter, but still be too tall so that the nipple taper prevents it from being seated all of the way down on the cap.
That's why some folks use a push stick to seat the caps.
And also why some cap brands work better than others.
Even magnum caps have more primer material inside the cap which can affect how well it seats on the nipple and whether the impact is cushioned or not.
Maybe if a cap fits loose, it can come up and off being seated on the nipple as each shot is fired.
Whereas a snug fitting #10 cap won't do that and will stay in place.
But then staying in place may result in too much clearance.

And that may also correlate to why the Slix Shot or Ampco nipples may work better.
If the cone is taller then that may effectively raise the caps increasing the hammer impact, and the caps may also seat better if the cones are taller by even a small amount.

There's still a chance that the cylinder is not remaining static when the hammer falls, or that there is slight interference with the hammer in the slot or both, in addition to the clearance related issues.

To be honest, .003 clearance seems a little bit excessive if it's an accurate measurement.
You may need to try different nipples, in addition to either shimming both the nipples and mainspring.
And maybe even try to slick up the hammer fall with a lubricant such as graphite or a compatible oil.

There may even be a way to modify how far the hammer can fall forward as someone else previously mentioned if the frame or hammer design interferes with or limits how far that it can fall.
That could be fairly simple.
It's a project to not give up on if you bought the gun at a good deal.
If Ruger will look at it then that's always a possibility.
But I know someone who had a defective ROA and Ruger offered him any current model as a replacement rather than fixing it since they didn't have the replacement parts needed.

I hope that #10 caps or #10 Remingtons are the simple solution.

Hey, if Ruger offers me a deal on a new gun, I'll take it (I've been eyeing that 45 colt/45 acp convertible) then buy another non-problem old army.

[megasupermagnum]

So the hammer is straight, minimal light comes by when held on a true flat surface. When mounted in the gun, a .015" feeler gauge passes between the frame and hammer above the pivot screw. However, a .022", which is the largest I had without going to the garage easily slides in below the pivot screw. So unless this is intentional, the frame is far out of square.

[arcticap]

You posted your photos while I was typing and editing for a long time.
I'm glad that you made some progress.

[rking22]

Good progress, narrowed down to a few components. Try backing the pivot screw out 1/2 turn and see if there is a change, perhaps only a bad screw.. Also look at the main spring strut interface with the slot in the hammer. My hammer is rather loose, when not in a sear notch. Actually pivots a bit, like the pivot pin has lots of clearance. The coil mainspring strut has a “right side up” is it correct? The ball on the strut end may have a burr, that would change direction as the rammer rotates. Last, if I see correctly the radiused part of the hammer is catching on the frame, slightly break the corners on the hammer so that it can slide across that contact rather than catching. Not really a radius but removing the sharp 90 deg corner with a round stone or 600 paper glued to a dowell. Doesn’t “fix” the misalignment but could eliminate enough drag to make it reliable.

[rking22]

If the contact is the hammer nose, note the slight 45 deg chamfer on the sides of my hammer. This gun has been 100% reliable.

[rking22]

If the contact is the hammer nose, note the slight 45 deg chamfer on the sides of my hammer. This gun has been 100% reliable. Looking closer at your first picture I think I see what you have. Mine will make contact there if I push the hammer left. Here is a picture of that face on mine, it seems to have a slightly broken edge as does the hammer. If you remove that displaced metal and break the edge with a needle file you may fine joy.

[arcticap]

Hey, if Ruger offers me a deal on a new gun, I'll take it (I've been eyeing that 45 colt/45 acp convertible) then buy another non-problem old army.

I would send it to Ruger before making any permanent modifications.
Especially if you don't want to jeopardize any chance of being offered a new replacement gun.
There's 3 possibilities.
1. They could fix it.
2. They claim to fix it, but send it back without it actually being fixed and 100% reliable.
3. They admit that they can't or won't fix it and offer you a new gun.

How it pans out could be up to the repair technician, if it needs parts, and whether he thinks that he can fix it or not.
The problems need to be outlined in a letter for the repair dept. and technician to read.
I don't know if they will send you a shipping label or not, but you can call and ask for one.
But I would tell them that the gun is in relatively new condition and has always had reliability issues due to factory defects.

[megasupermagnum]

Great news! I was slow to send it to Ruger, but it was there and back in 2 weeks. I got a note back with it that says all they did was replace the hammer, and test it with Remington #11 caps. The first thing I noticed is that the hammer has much less slop, like every other Ruger I have, and most importantly, it doesn't seem to hit the frame at all anymore.

This made all the difference in the world. Using my CCI #11 magnum caps, all 6 went off on the Ruger nipples, and I repeated it a second time. I swapped in the TOTW nipples, and shot 18 in a row without a hiccup. I can finally do some real shooting with this. Thanks Ruger, this is why all but one of my revolvers are Ruger's.

[rking22]

Excellent! Glad they fixed you up, I was under the impression they no longer had parts. Glad that is not the case. They are very good shooters, if a bit on the heavy side for carry.

[megasupermagnum]

They flat out told me, they don't have much for parts for these, but I can send it in for a look. Apparently I got lucky. The only question I have, is how many parts could there be specific to the Old Army? I'm guessing most of the trigger parts are the same as any other old model Blackhawk, except for the hammer. The sights should be the same. Other than that, it's just a frame and cylinder, which do not fail. Maybe the loading lever parts break?

No matter, they fixed mine.

[Ozark mike]

I imagine the spring would be heavier for smashing the caps vs a small diameter firing pin poking primers

[rking22]

I suspect lots of the small parts may be common. Seemed you needed a hammer and that is definitely different! Glad you got it back running, blackhawks are dime a dozen unlike ROAs! Get the Blackhawk, next year

[stubshaft]

I replaced the nipples in all of my ROA's with SlixShot nipples. They are and have always been reliable and accurate, I can honestly say that I have never had an issue with an ROA.